I am wondering if anyone knows how to make DIY FPV gear (possibly cheaper than bought).

I would like it to either work with my 900MHz system I bought from hobbyking or to be a lower frequency (eg. 1 to 30MHz) but any frequency will do if push come to shove. If it can work on a 3s lipo and the power is adjustable (in the plans not physically eg. Use a different resistor to increase the power) it would be perfect.

I cannot speak for other people who would like to do this but I am happy to jump into the deep end with this project. I am happy with a soldering iron in hand and can do basic electrical work, it is just I do not know what I have to do.

I understand that it may not work as well or be as light and compact as the commercial product but I would get more enjoyment out of making rather than buying.

Thanks already,
Darcy

The GHz soldering is behind hobby tools and skills.
The best results you can have is to get some 5.8GHz modules for $35, and use them to make a system able to reach 15km or even more.
No joking, this is the electronics inside the system that holds current 18km record, for this class of gear.
But beware, the secret of this range are the antennas ! You will have a lot of "tinkering", in the real sense, to build the antennas able to give you such results.